Climate models The ability of ecosystems to adapt to climate change has been put under the microscope and the news is good for tuna and tropical rainforests.

Two separate studies, both including Australian researchers, have looked at the resilience and responses to climate change of Pacific fisheries and aquaculture and tropical rainforests around the world.

The studies show the future is not as bleak as once thought and according to co-author on the rainforest paper, Professor Owen Atkin, at the Australian National University, this is the result of improved modelling that draws on expertise across disciplines.

The fisheries study, published today in Nature Climate Change shows changes to ocean currents and increased ocean temperatures will lead to increased tuna stocks in some regions such as Kiribati as prime feeding grounds move east of longitude 170 °E.

Freshwater fisheries production in Melanesia is also expected to improve, with higher rainfall expanding river flow, but coral reef fisheries will decline with coral cover estimated to decrease by between 10-20 per cent by 2050.

But any potential increase in freshwater fisheries will be negated if industries such as mining and agriculture continue to heavily pollute waterways, say the researchers.

Not uniform

"There is no black and white. Climate change will have impacts - some will be positive and some will be negative," he says.

Critically for the implementation of policies to address these impacts, the study shows population growth and coastal development are likely to "overshadow" the effect of climate change, says Matear.

Population growth combined with the drop in coral reef fish numbers, for example, will widen the gap between fish needed to feed people in Pacific Islands and the fish available through sustainable fishing from the reefs.

Matear says the onus is on governments in the region to address both drivers of change.

He says the importance of the work, which includes experts in fisheries, reefs, climate and oceanography, is that it highlights the need for an "integrated approach" when modelling.

This is a view supported by Atkin and Professor John Lloyd, at James Cook University, who were involved in examining the impacts of climate change on tropical rainforests.

Their study overturns a 2000 Nature paper, led by co-author Professor Peter Cox at the University of Exeter that predicted climate change would lead to the demise of the Amazon rainforests.

The fear then was the die-back of the Amazon forests - which are a major carbon store - would result in the release of huge amounts carbon into the atmosphere that would accelerate global warming.

No die back

However the new study - also led by Cox and published today in Nature Geoscience - shows tropical rainforests in Africa, Asia and the Americas could grow in size as increased carbon dioxide in the atmosphere promotes plant growth in a process known as "carbon fertilisation".

"On its own, higher temperatures [as a result of climate change] will probably have a detrimental effect," says Lloyd, "but because CO2 stimulates photosynthesis [and plant growth] this negative impact is more or less offset."

Lloyd says the increase in tropical rainforests should slow global temperature rise and that these rainforests could keep "helping" us in this way through the 21st century.

"What these forests do in the future matters," he says. "If we are able to maintain these forest canopies, the rate at which carbon dioxide increases in the atmosphere will slow and the world is not going to heat up quite as fast."

Atkin says the new finding highlights the importance of a "growing dialogue between different members of the scientific community".

He says in the past, physicists and mathematicians developed models without much input from experts in fields such as plant physiology and tropical ecology.

In the past 15 years there have been enormous developments in understanding of how plants will adapt to climate change and the new finding reflects that, he says.